On the Possibility of Multiple Valence Superatoms

It was recently demonstrated that an Al$_{13}$ cluster behaves like a halogen atom while an Al$_{14}^{ }$ cluster has properties analogous to an alkaline earth atom in gas phase clusters containing aluminum and iodine atoms. These observations, together with findings that Al$_{13}^{-}$ is inert like a rare gas atom, have reinforced the idea that chosen clusters can exhibit chemical behaviors reminiscent of atoms in the periodic table, offering the exciting prospect of a new dimension of the periodic table formed by cluster elements, called the superatoms. As the properties of the clusters can be controlled by size and composition, the superatoms offer the potential to create unique compounds with tailored properties. In this paper, we provide evidence of a new class of superatoms that exhibit multiple valences, like some of the atoms in the periodic table, and hence have the potential to form stable compounds when combined with diverse atoms.